While we slowly ramp up to release mobile phone contact sync, using my own contacts as test data I realized that once I had merged my phone's address book and Thunderbird's address book, I had quite a few contacts duplicated due to them having different names with different information in them. So I had one of those "you know what would be cool...?" kind of moments, and started working on a feature that would let me merge contacts on the web, saving me hours of copy-n-paste.
A few weeks later, an initial pass at that feature has rolled out! Yay agile software development!

There are a few tweaks to the contacts interface, and you will see a new option:

So, for example, let's pretend you have 2 contacts that are the same person but have an extra name in one of them, one of them has his phone number, the other, his email:

and

We go to our new merge feature and select both of them:

Finally, we get a preview of what this will look like:

Done!

Plans for the future are:

- Allow conflict resolution when the contact has 2 fields that are the same but have different values
- Allow editing the contact in the merge preview
- Allow merging from the contacts page instead of a separate page
- Use this same mechanism when conflicts arise in couchdb merging contacts
Also, contact syncing from thousands of mobile phones will be opened up for a public alpha very very very soon. Stay tuned!